Facebook announced on Monday that it is shutting down a buying platform that the company had been testing since last year, through its ad server, Atlas. The move comes after Facebook discovered the program was plagued by low-value advertising—in large part due to the popularity of banner ads—which means marketers were wasting ad dollars on content that did not attract enough eyeballs.

Facebook’s VP of ad tech, Brian Boland, told The Information that his team "saw a ton of waste, a ton of fraud" from the banner ads being served by the program; they found that those types of ads were often delivered to bots, rather than real users. In an Atlas blog post, the ad-tech team revealed that the two formats that did offer "significant value" were native and video ads. As Boland told Business Insider, those formats were seven times more successful than banner ads.

Though Facebook has abandoned its current ad-buying platform, the company eventually plans to create one that focuses instead on serving high-value native and video ads, according to The Information. In doing so, Facebook may have a leg up on Google's DoubleClick, which dominates the ad server space but was built for desktop rather than mobile devices.